Numerical control system and method

ABSTRACT

A control system having a stored program digital computer for transmitting commands to digital servos for one or a plurality of punch presses; for changing new commands to correct for preceding servo errors and/or mechanical tolerance errors in the servos; the monitoring machine tool and servo condition and supervising punching, tool change and positioning operations; and having provision for assisting in the generation of coded record command tapes on the basis of incremental and/or absolute dimensional input, on a time sharing basis with automatic operation of the servos from a previously generated record tape.

United States Patent Inventor Kenneth Leonard Slawson Depew, N.Y.

Appl. No. 744,392

Filed July 12, 1968 Patented Jan. 11, 1972 Assignee l-loudaille Industries, Inc.

Buffalo, N.Y. Continuation-impart of application Ser. No. 652,968, July 12, 1967, now abandoned. This application July 12, 1968, Ser. No. 744,392

NUMERICAL CONTROL SYSTEM AND METHOD 42 Claims, 90 Drawing Figs.

U.S.Cl ..235/15l.ll, 318/568, 318/570, 318/601, 340/172.5 Int. Cl ..G06f 15/46, B23q 21/00 Field of Search ,.235/151.11,

References Cited UNITED STATES PATENTS 3,254,203 5/1966 Kveim 235/l5l.1l X 3,328,655 6/1967 Tripp 235/197 X 3,390,315 6/1968 McDonough et a1. 235/151.l1 X 3,430,036 2/1969 Patrick 235/151.11 3,465,298 2/1969 Duke etal. 235/151.1 l X Primary Examiner Malcolm A. Morrison Assistant Examiner- Felix D. Gruber Attorney-Hill, Sherman, Meroni, Gross & Simpson PATENTEB JAM 1 m2 MEI 03 0F 69 PATENTED JAN? 1 1972 SHEET UQUF 69 wzysazz PATENTEU JAN: 1 i972 SHEEI CSUF 69 PATENTED JAN} 1 I972 SHEET USUF 69 K m c7 A. 54 AM/JQ/I/ ATTORNEY:

PATENTEI] JAN? 1 I972 SHEET 1011f 69 PATENTED Jan: I I972 SHEET llUF 69 PATENTED JAN? 1 1972 SHEET 12UF 69 PATENTEU JAM 1 1972 SHEET 130F 69 PAIENIEIIJMIIBIZ 3.634.662

sum lSIIF 69 '5 CLEAR TOOL LIGHT FETCH A CHARACTER FROM TAPE PUT START ADDRESS OF: TAPE PREP. INTO LOCATION 0 READER INTERRUPT SERVICE INTO RISP CLOCK INTERRUPT SERVICE A INTO CLISP I RESET BLOCK COUNTER WAIT WAIT FOR A CLOCK INTERRUPT SET READER POINTER (0 OUT SWITCHES SET BLOCK COUNT SWITCH SET BLOCK END SWITCH CLEAR CLOCK AND DATA RESET BITS CLEAR STATUSWORD FLAG INIT b CLEAR TOOL LIGHT AND WAIT REVERSE READER BITS WAIT FOR A CLOCK INTERRUIT DATA BLOCK COMPLETE? PARITY YES ERROR? TURN ON ERROR LIGHT TURN OFF RUN FLIP FLOP IIVEITOI BETH SLA'SOI ATTORIEYS PATENIED JAM 1 I972 3,634,662

SHEET 18 0F 69 ID MOVE EXE TE THE MOVE, IF ANY WAIT WAIT FOR A CLOCK INTERRUII STATUS CLEAR? COMMAND EXECUTE SPECIAL AND LIGHT COMMANDS COUNT NUMBER OF ODD BITS CLEAR ACCUMULATOR AND LINK IS THERE AN ODD NUMBER OF BITS? INCREMENT YES RETURN ADDRESS 'IURN 0N PARITY SWITCH RETURN INVENTOR l g KENNETH 2L SLAWSOI j ATTORNEYS msmemnmz 3,634,662 SHEET 17UF 69 PUT IJOW Y AXIS INTO AC PUT LOW SIDE OF Y MOVE INTO AC CLEAR LOW Y AXIS LOAD AC IN LOW Y AXIS SAVE LINK SET X AXIS SYNCHRONIZER PUT UPPER Y AXIS INTO AC PUT LOW X-AXIS IN'IO AC PUT LOW SIDE OI X MOVE INTO AC CLEAR LOW X-AXIS AND LOAD PUT LINK INTO AC SAVE IT IN LINK PUT UPPER X- AXIS INTO ACCUMULATOR MAKE IT TRUE COMPLEMENT PUT HIGH SIDE OF Y MOVE INTO AC CLEAR HIGH Y AXIS LOAD AC IN HIGH Y AXIS RELEASE Y AXIS SYNCHRONIZER MAKE IT TRUE COMPLEM ISNT EXECUTE THE MOVE PUT HIGH SIDE OF X MOVE INTO AC CLEAR HIGH X AXIS COUNTER RELEASE X AXIS SYNCHRONIZER SET Y AXIS SYNCHRONIZER IIIVEH'I'OR I SLMISOI TORIBYS PATENIEBJAmm 8. 2 SHEET 180! 69 INHIBIT PUNCH BIT SET? CLEAR ACCUMULATOR CLEA R LINK STEP MODE SWITCH SET? IS REWIND BIT SET? PUNCH RESET BLOCK START RESET BLOCK IiND FETCH A CHARAC'IER (TO PERMIT NEXT DATA TO BIL FETCIIIiD BY RIS) S IA'IUS CLEAR? IS RETRAC'I COMMANI BIT SET? WAIT WAIT FOR A READER OR CLOCK INTERRUPT CLEAR X AND Y AXIS BEFORE RETRACT RETRACT INVENTOR SLAHSON KENNETH A TORNEYS Pmmmm 1m: 3.634.662 SHEET 18 0F 69 STEP MODE SWITCH SET? 'IOOL LIGHT BIT SET? TURN RUN FLIP FIDP OFF TURN TOOL LIGHT ON LDAD POSITIO BIT SET? STOP BIT TURN IDAD POSITION LIGHT ON AND PUT SIDE GAUGE UP 'IURN RUN FLIP FLOP OFF RETURN RETURN TO MAIN IDOP I I KENNETH SLAISOI ATTORNEYS 

1. A machine tool control system for controlling positioning operations along respective X- and Y-axes of a machine tool, said control system comprising a. source means for supplying machine tool positioning instructions, b. a digital computer having as part thereof a computer memory and a computer output, said computer being operatively connectable to said source means to receive said machine tool positioning instructions therefrom, said computer memory having stored therein a machine tool control program for controlling the operation of the computer in transmission to said computer output of X- and Y-axis machine tool displacement commands in accordance with the machine tool positioning instructions supplied to said computer, c. machine tool positioning control means operatively connectable with parts of the machine tool which are movable along the X- and Y-axes for controlling movement of such parts along the X- and Y-axes of the machine tool, and comprising Xand Y-axis counters for registering displacement commands with respect to the respective axes and for receiving and counting X and Y-axis motion pulses which are generated as a function of displacement of the parts of the machine tool along the X- and Y-axes, respectively, and d. output means operatively connectable with said computer output and with said X- and Y-axis counters of said machine tool positioning control means to provide a direct and immediate connection between said computer output and said Xand Y-axis counters for the transmission of said X- and Y-axis machine tool displacement commands thereto without any intervening storage of said displacement commands.
 2. A machine tool control system for generating displacement commands and for controlling movement of parts of a machine tool in accordance therewith, said control system comprising a. source means for supplying successive machine tool control instructions of a previously established sequence, b. manually controlled input means operable to produce coded input signals as manually selected by an operator, c. a digital computer operatively connectable to said source means to receive said previously established sequence of machine tool control instructions therefrom and operatively connectable to said manually controlled input means to receive said coded input signals therefrom, said digital computer including a computer memory storing a program for controlling operation of said computer to convert said previously established sequence of machine tool control instructions to displacement commands specifying movements of the parts of the machine tool so as to execute said previously established sequence of machine tool control instructions and to convert said coded input signals into a newly generated sequence of machine tool control instructions as determined by the manually selective control of said input means, and d. machine tool control means operatively connectable to the machine tool and connected on line with said digital computer and responsive to said displacement commands produced by said computer to conTrol movements of the parts of the machine tool in accordance therewith.
 3. A machine tool control system in accordance with claim 2 with said manually controlled input means being operable to produce coded input signals representing a plural digit decimal number with respect to any one of a plurality of machine tool axes along which respective parts of the machine tool are movable, and said digital computer including computer memory locations and being operable under the control of said program to store said newly generated sequence of machine tool control instructions in said computer memory locations as successive blocks having successive block identifying numbers, and being responsive to coded input signals representing a plural digit decimal number with respect to successive ones of said plurality of machine tool axes to store said plural digit decimal numbers as representing displacement values relative to said machine tool axes in one of said successive blocks having one of said successive block identifying numbers.
 4. A machine tool control system in accordance with claim 3 with said manually controlled input means being operable to produce coded input signals including a coded ''''list'''' signal for instructing the digital computer to list all blocks of said newly generated sequence of machine tool control instructions stored in said computer memory locations, and said digital computer being operable under the control of said program to respond to said coded ''''list'''' signal to list said blocks of said newly generated sequence of machine tool control instructions together with said block identifying numbers in the sequence of said successive block identifying numbers.
 5. A machine tool control system in accordance with claim 3 with said manually controlled input means being operable to produce coded input signals including a ''''delete'''' signal instructing the computer to delete identified blocks of said newly generated sequence of machine tool control instructions in said computer memory locations, and said digital computer being operable under the control of said program to respond to said ''''delete'''' signal to delete blocks of said newly generated sequence of machine tool control instructions from said computer memory locations as identified by said ''''delete'''' signal.
 6. A machine tool control system in accordance with claim 2 with said manually controlled input means being operable to supply to said computer coded input signals including a coded incremental displacement signal expressing displacement incrementally with respect to the next previous position of a part of the machine tool along a given machine tool axis, and including a coded absolute displacement signal expressing a desired new position of a part of the machine tool with respect to a given machine tool axis and with respect to a predetermined reference point of the machine tool, and said digital computer including computer memory locations and being operable under the control of said program to convert said coded incremental displacement signal to a corresponding machine tool control instruction and operable to store said corresponding machine tool control instruction in one of said computer memory locations, and being operable under the control of said program to respond to said coded absolute displacement signal to generate a corresponding incremental machine tool control instruction expressing displacement with respect to the next previous one of said sequence of machine tool control instructions in said computer memory locations, and operable to store said corresponding incremental machine tool control instruction in said computer memory locations.
 7. A machine tool control system in accordance with claim 2 with said manually controlled input means being operable to supply to said digital computer coded input signals including a coded incremental displacement signal representing an incremental displacement value expressed incrementally with respect to tHe next previous commanded position with respect to a given machine tool axis, said digital computer including computer memory locations and being operable under the control of said program to store said newly generated sequence of machine tool control instructions as successive blocks of machine tool control data in said computer memory locations, said digital computer being operable under the control of said program to compute respective accumulated absolute displacement values for said successive blocks of machine tool control data representing respective commanded positions with respect to a common reference point along a given machine tool axis and to store said accumulated absolute displacement values as part of the respective blocks in said computer memory locations, and being operable under the control of said program to respond to said coded incremental displacement signal to algebraically combine the incremental displacement value represented thereby with the accumulated displacement value of the preceding block stored in said computer memory locations to obtain an accumulated displacement value for storage as part of a further block of machine tool control data in said computer memory locations.
 8. A machine tool control system in accordance with claim 7 with said digital computer being operable under the control of the program to store in said computer memory locations as part of each successive block an incremental displacement value and the corresponding accumulated absolute displacement value.
 9. A machine tool control system in accordance with claim 8 with said digital computer being operable under the control of said program to print out from said computer memory locations successive blocks of machine tool control data including both said incremental displacement values and said corresponding accumulated absolute displacement values.
 10. In combination with a machine tool having X- and Y-axis drive circuits for positioning parts of the machine tool along respective X- and Y-axes of the machine tool, a machine tool control system comprising a. source means for supplying machine tool positioning instructions, b. a digital computer including a computer memory and a computer output, said computer being operatively connectable to said source means to receive said machine tool positioning instructions therefrom, said computer memory having stored therein a machine tool control program for controlling the transmission to said computer output of X- and Y-axis machine tool displacement commands in accordance with the machine tool positioning instructions supplied to said computer by said source means, c. a machine tool positioning control operatively connectable with said X- and Y-drive circuits of said machine tool for controlling positioning movement of the respective parts of the machine tool along the respective X- and Y-axes of the machine tool, and d. output gates directly connected with said computer output and directly connected with said machine tool positioning control and selectively providing a direct and immediate multiple channel connection between said computer output and said machine tool positioning control for the transmission of said X- and Y-axis machine tool displacement commands thereto in coded form without any intervening storage of said displacement commands, for effecting positioning of said parts by means of said X- and Y-drive circuits in accordance with said X- and Y-machine tool displacement commands produced by said digital computer under the control of said machine tool control program.
 11. The combination of claim 10 with X- and Y-digital feedback components coupled with the respective drive circuits for generating digital feedback pulses as a function of movement of said parts of said machine tool along the respective axes, said machine tool control comprising X- and Y-axis axis counting circuits for initially registering said X- and Y-axis machine tool diSplacement commands as initial count values therein, and for responding to digital feedback pulses from the respective X- and Y-digital feedback components to progressively reduce the count values registered in the respective counting circuits as said parts approach the commanded position corresponding to said X- and Y-axis machine tool displacement commands, said machine tool control further comprising X- and Y-axis converter circuits connected respectively with said X- and Y-axis counting circuits and with said X- and Y-axis drive circuits for responding to the count values registered in said counting circuits to generate analog error signals as a function of said count values and for transmitting said analog error signals to said drive circuits to control the positioning of said parts in accordance therewith, said output gates being connected directly to said X- and Y-axis counting circuits for direct and immediate transmission of said X- and Y-axis machine tool displacement commands from said computer output to said counting circuits, to effect a corresponding positioning operation by means of said drive circuits.
 12. The combination of claim 11 with said X- and Y-axis digital feedback components supplying digital feedback pulses for each predetermined increment of movement of said parts of the machine tool along the respective axes, said parts of the machine tool having predetermined ranges of movement along the respective axes which correspond to predetermined numbers of said digital feedback pulses, and said X and Y-axis counting circuits having count capacities at least equal to the respective predetermined numbers of said digital feedback pulses corresponding to said predetermined ranges of movement of said parts of said machine tool along the respective axes.
 13. The combination of claim 11 with said machine tool control comprising a move-complete circuit controlled by the count values in said X- and Y-axis counting circuits to establish a move-complete condition when both the counting circuits indicate that said parts of the machine tool are substantially at the commanded position with respect to the X and Y-axes and said computer under the control of said machine tool control program being operable to detect said move-complete condition.
 14. The combination of claim 10 with auxiliary function circuitry operatively connected via a direct and immediate transmission path with said computer and with said machine tool and responsive to an auxiliary function command for causing the machine tool to execute an auxiliary function other than a positioning operation, and said computer under the control of said machine tool control program being operable at the completion of a machine tool positioning operation to transmit said auxiliary function command via said direct and immediate transmission path to said auxiliary function circuitry for causing the machine tool to execute said auxiliary function.
 15. The combination of claim 11 with absolute position readout means connected with the X- and Y-axis digital feedback components and responsive to said digital feedback pulses to maintain a visual count thereof for indicating the position of said parts of said machine tool along the respective axes in relation to a reference point, throughout successive positioning operations, to provide for verification of a sequence of said machine tool positioning instructions supplied to said computer from said source means, by visual inspection of said absolute position readout means.
 16. The combination of claim 15 with means connected with said digital computer for placing said computer in a step mode of operation whereby said digital computer under the control of said machine tool control program in said step mode of operation stops the machine tool after the execution of each machine tool positioning instruction from said source means, to provide for visual inspection of said readout means.
 17. In combination, a. a machine tool having parts thereof movable along respective machine tool axes of the machine tool, b. machine tool closed loop digital servos for controlling positioning of said parts of the machine tool along the respective axes in accordance with machine tool displacement commands supplied thereto in digital form, said servos comprising respective machine tool drive circuits connected with the machine tool for driving said parts thereof along the respective machine tool axes in accordance with respective analog error signals, comprising respective digital feedback components driven by the respective drive circuits in accordance with the movement of said parts of the machine tool along the respective machine axes and operable to generate digital feedback signals as a function of such movement, and comprising digital control circuits connected with said digital feedback components and operable to register said machine tool displacement commands and operable to respond to said digital feedback signals from said digital feedback components and to generate said analog error signals in accordance with any error between said machine tool displacement commands and said digital feedback signals for the respective machine tool axes, and connected with said drive circuits to supply said analog error signals to said drive circuits, c. a source for supplying machine tool positioning instructions, d. a stored program digital computer connected with said source and including a computer memory containing a stored machine tool control program, said digital computer under the control of said stored machine tool control program being operable to respond to machine tool positioning instructions from said source and to convert said positioning instructions to said machine tool displacement commands in said digital form, and e. output circuitry connected directly with said computer and connected directly with said digital control circuits and providing a direct and immediate connection between said stored program digital computer and said digital control circuits for transmitting said machine tool displacement commands in said digital form to said digital control circuits, thereby to cause execution of the machine tool positioning instructions supplied by said source.
 18. The combination of claim 17 with said machine tool closed loop digital servos including in-position detectors for the respective axes for generating in-position signals when the respective parts of said machine tool substantially attain the respective commanded positions along the respective axes as represented by said machine tool displacement commands registered by said digital control circuits, and including a move-complete circuit connected with said in-position detectors and responsive to the simultaneous existence of in-position signals from both of said in-position detectors for a predetermined substantial time interval to establish a move-complete condition, said stored program digital computer under the control of said stored machine tool control program being operable to respond to said move-complete condition as signalling that a positioning operation of said machine tool closed loop digital servos has been completed.
 19. The combination of claim 18 with said move-complete circuit being adjustable to provide a predetermined substantial range of time intervals, thereby to require simultaneous existence of said in-position signals from both of said in-position detectors over a predetermined substantial time interval which time interval is adjustable over said predetermined substantial range.
 20. The combination of claim 18 with said move-complete circuit comprising an adjustable time delay component having its time delay adjustable over a substantial range with the time delay of said component determining said predetermined substantial time interval during which said in-position signals must be present to establish said move-complete condition.
 21. The combination of claim 18 with sAid move-complete circuit requiring that said in-position signals both be present for a time interval of the order of 100 milliseconds before said move-complete condition is established.
 22. The combination of claim 18 with said stored program digital computer under the control of said machine tool control program being responsive to the existence of said move-complete condition to selectively execute at least one special command.
 23. The combination of claim 18 with said machine tool being responsive to a special command to execute a machine tool function at the completion of a positioning operation of said machine tool closed loop digital servos, said stored program digital computer under the control of said machine tool control program being responsive to said move-complete condition of said move-complete circuit to selectively generate said special command, and an interface circuit connecting via a direct and immediate transmission path said stored program digital computer with said machine tool for transmitting said special command to said machine tool thereby to cause said machine tool to execute said machine tool function.
 24. The combination of claim 18 with said machine tool comprising a punch press responsive to a special punch command to execute a punching operation, said stored program digital computer under the control of said machine tool control program being connected with said move-complete circuit and being responsive to said move-complete condition thereof to selectively generate said special punch command, and an interface circuit connecting said stored program digital computer on line with said machine tool for transmitting said special punch command to said machine tool thereby to cause said machine tool to execute said punching operation at the completion of a positioning operation of said machine tool closed loop digital servos.
 25. In combination, a. a machine tool having parts thereof movable along respective machine tool axes for positioning a workpiece with respect to a machine tool operating position, b. a source for supplying successive machine tool control instructions of a previously established sequence for controlling movement of said parts of said machine tool with respect to said axes, c. a manually controlled input device operable to produce coded input signals as manually selected by an operator, d. a stored program digital computer operatively connected to said source and to said manually controlled input device and comprising a computer memory containing first and second stored programs, said digital computer being operable under the control of said first stored program to receive said previously established sequence of machine tool control instructions from said source and to convert said previously established sequence of machine tool control instructions to displacement commands specifying movement of said parts of said machine tool in accordance with said previously established sequence, and operable under the control of said second program for online communication with said manually controlled input device to convert said coded input signals into newly generated machine tool control instructions as determined by the manually selective control of said input device, and e. a machine tool control operatively connectable to the machine tool and to said digital computer and responsive to said displacement commands produced by said digital computer to control movements of the parts of said machine tool in accordance therewith.
 26. The combination of claim 25 with said stored program digital computer providing for contemporaneous operation of said manually controlled input device and said source on a time-sharing basis.
 27. The combination of claim 25 with said manually controlled input device being operable to produce coded input signals as manually selected by an operator representing a newly generated sequence of machine tool control instructions, and said stored program digital computer beIng operable under the control of said second stored program to convert said coded input signals into said newly generated sequence of machine tool control instructions and to store said newly generated sequence of machine tool control instructions in said computer memory.
 28. The combination of claim 25 with said manually controlled input device being operable to produce coded input signals representing machine tool control instructions in both incremental and absolute form, and said stored program digital computer being operable under the control of said second stored program to accept said coded input signals in both said incremental and said absolute form and to convert both types of said coded input signals to machine tool control instructions which can be processed by said digital computer under the control of said first program so as to be effective for operating said machine tool control.
 29. The combination of claim 25 with said combination including a plurality of machine tools each having parts thereof movable with respect to a plurality of axes to position respective workpieces with respect to respective machine tool operating positions, said machine tool control comprising respective machine tool control units for controlling movement of said parts along the respective axes of the respective machine tools, and said stored program digital computer being operable to control positioning operations of each of said machine tool control units.
 30. The combination of claim 25 with said combination including a plurality of manually controlled input devices operable to produce respective series of coded input signals as manually selected by respective operators thereof, said stored program digital computer being operably connected for online communication with each of said input devices so as to provide for the contemporaneous preparation of a plurality of newly generated sequences of machine tool instructions as determined by the manually selective control of the respective input devices.
 31. In combination, a machine tool having a worktable for displacement along respective axes in positioning a workpiece relative to a machine tool operating position, a machine tool control connected with said machine tool for controlling positioning operations of said worktable in accordance with machine tool displacement commands, a stored program digital computer including a computer memory containing a stored program for controlling the computer to respond to coded input signals to generate said displacement commands in accordance therewith, and connected with said machine tool control, a manually controlled input device connected with said digital computer and operable to produce said coded input signals as manually selected by an operator for transmission to said digital computer, and a coded record input device connected with said computer and having a record with a stored previously established sequence of machine tool control instructions thereon for sequential transmission to said digital computer, said digital computer under the control of said stored program being operable to convert said previously established sequence of machine tool instructions from said coded record input device to displacement commands corresponding to said previously established sequence of machine tool instructions for transmission to said machine tool control, and said digital computer under the control of said stored program being responsive to said manually controlled input device and said coded record input device on a time-sharing basis.
 32. In combination, a machine tool having a worktable for displacement along respective axes in positioning a workpiece relative to a machine tool operating position, a machine tool control connected with said machine tool for controlling positioning operations of said worktable in accordance with machine tool displacement commands, a stored program digital computer including a computer memory containing a stored program for controlling the Computer to respond to coded input signals to generate said displacement commands in accordance therewith, and connected with said machine tool control, an input device connected on line with said computer and operable to generate a sequence of sets of coded input signals each such set of coded input signals representing a block of machine tool control data, and each block of machine tool control data representing respective machine tool displacement commands for the respective axes for producing a single move of the workpiece relative to the machine tool operating position, said stored program digital computer being operable under the control of said stored program to respond to each of said sets of coded input signals to generate a corresponding block of machine tool displacement commands for the respective axes, and said stored program digital computer being operable under the control of said stored program to transmit the blocks of machine tool displacement commands from said stored program digital computer to said machine tool control, for causing the machine tool control to execute the successive moves represented by said sequence of sets of coded input signals.
 33. The combination of claim 32 with said input device being operable to generate a pattern type coded input signal representing a series of moves of a workpiece relative to the machine tool operating position, said stored program digital computer being operable under the control of said stored program to respond to said pattern type coded input signal to calculate a series of blocks of machine tool control data representing said series of moves of said workpiece relative to said machine tool operating position.
 34. In combination, a machine tool having a worktable for displacement along respective axes in positioning a workpiece relative to a machine tool operating position, a machine tool control connected with said machine tool for controlling positioning operations of said worktable in accordance with machine tool displacement commands, a stored program digital computer including a computer memory containing a stored program for controlling the computer to respond to coded input signals to generate said displacement commands in accordance therewith, and connected with said machine tool control, an input device connected on line with said computer and being operable to generate a sequence of sets of coded input signals, each such set representing a corresponding block of machine tool control data and representing a corresponding move of the machine tool, said sequence of sets of coded input signals thus representing a sequence of said blocks of machine tool control data, said input device further being operable to generate a pattern type coded input signal calling for a repetition of a previous series of movements of the machine tool and identifying a previous series of said blocks of said sequence corresponding to said previous series of movements, said stored program digital computer being operable under the control of said stored program to respond to each of said sets of coded input signals to generate the corresponding block of machine control data and to store the sequence of said blocks of machine control data so generated in said computer memory, and said stored program digital computer being operable under the control of said stored program to respond to said pattern-type coded input signal to call up from said computer memory the previous series of said blocks of machine control data identified by said pattern-type coded input signal and to generate a new series of blocks of machine control data substantially identical to said previous series.
 35. In combination, a machine tool having a worktable for displacement along respective axes in positioning a workpiece relative to a machine tool operating position, a machine tool control connected with said machine tool for controlling positioning operations of said worktable in accordance with machine tool displacement commands, a stored program digitAl computer including a computer memory containing a stored program for controlling the computer to respond to coded input signals to generate said displacement commands in accordance therewith, and connected with said machine tool control, an input device connected on line with said computer and being operable to generate a sequence of sets of coded input signals, each such set representing a corresponding block of machine control data and representing a movement of the worktable of the machine tool along the respective axes, the sequence of sets of coded input signals thus representing a sequence of blocks of machine control data and a corresponding sequence of movements of the machine tool, said input device further being operable to generate a pattern-type coded input signal representing a mirror image of a previous series of movements and identifying a previous series of said blocks of said sequence of blocks corresponding to said previous series of movements, said stored program digital computer being operable under the control of said stored program to respond to each of said sets of coded input signals to generate the corresponding block of machine control data and to store the sequence of said blocks of machine control data so generated in said computer memory, and said stored program digital computer being operable under the control of said stored program to respond to said pattern-type coded input signal to call up from said computer memory the previous series of said blocks identified by said pattern-type coded input signal, and to generate a new series of blocks of machine tool control data based on said previous series but representing a series of movements which constitute a mirror image of the previous series of movements.
 36. In combination, a machine tool having a worktable for displacement along respective axes in positioning a workpiece relative to a machine tool operating position, a machine tool control connected with said machine tool for controlling positioning operations of said worktable in accordance with machine tool displacement commands, a stored program digital computer including a computer memory containing a stored program for controlling the computer to respond to coded input signals to generate said displacement commands in accordance therewith, and connected with said machine tool control, an input device connected on line with said computer and being operable to generate a coded input signal representing a limit value relative to a given reference point which is a function of the size of the workpiece, said input device further being operable to generate a sequence of sets of coded input signals, each such set representing a corresponding block of machine control data and representing a respective movement of the worktable along the respective axes, said sequence of sets of coded input signals thus corresponding to a sequence of blocks of machine tool control data representing a sequence of movements of the worktable, said input device further being operable to generate a pattern-type coded input signal calling for a movement of the worktable from a presently attained position represented by the last of the sequence of blocks of machine tool control data to an offset position with said machine tool operating position offset from the workpiece by a predetermined distance, said stored program digital computer being operable under the control of said stored program to store at a predetermined location in said computer memory said limit value relative to said given reference point, said stored program digital computer being further operable under the control of said stored program to respond to each of said sets of coded input signals to generate the corresponding block of machine tool control data and to store the sequence of said blocks of machine tool control data so generated in said computer memory, and to respond to said pattern-type coded input signal to call up from said computer memory said limit value relative to said given reference Point and said last of the sequence of blocks of machine tool control data and to calculate from the absolute displacement value represented by said last of said sequence of blocks of machine tool control data and said limit value a further block of machine tool data corresponding to a move of the worktable from said presently attained position represented by said last of said sequence of blocks to said offset position with said machine tool operating position offset from said workpiece by said predetermined distance.
 37. The combination of claim 36 with said stored program digital computer being operable under the control of said stored program to respond to a further set of coded input signals supplied by said input device following said pattern-type coded input signal and representing an incremental movement of the worktable relative to said presently attained position to calculate the required incremental displacement value for movement of the worktable from said offset position to the new position represented by said further set of coded input signals.
 38. In combination, a machine tool having a worktable for displacement along respective axes in positioning a workpiece relative to a machine tool operating position, a machine tool control connected with said machine tool for controlling positioning operations of said worktable in accordance with machine tool displacement commands, a stored program digital computer including a computer memory containing a stored program for controlling the computer to respond to coded input signals to generate said displacement commands in accordance therewith, and connected with said machine tool control, an input device operatively connectable on line with said stored program digital computer and operable to generate an ''''initial'''' coded input signal signalling that a sequence of machine tool control data is to be generated representing successive movements of the worktable along the respective axes in positioning a given workpiece relative to the machine tool operating position, and operable to generate a sequence of digit-representing coded input signals for representing plural digit decimal numbers, said stored program digital computer being operable under the control of said stored program to respond to said ''''initial'''' coded input signal to signal a request for a limit value relative to a given reference point which is a function of the size of the given workpiece, said stored program digital computer then being automatically operable under the control of said stored program to store the sequence of digit-representing coded input signals from the input device representing said limit value in said computer memory for subsequent use by said computer in connection with the generation of said sequence of machine tool control data.
 39. In combination a. a machine tool system for effecting a machine tool operation at an operating position, and including a worktable for movement along respective axes in positioning a workpiece relative to said operating position, and worktable drives for driving the worktable relative to the respective axes, said machine tool system including a machine tool control operably connectable on line with said worktable drives and operable in response to machine tool displacement commands to control the operation of said worktable drives in positioning a workpiece, b. an input device operable to produce displacement-type coded input signals representing machine tool displacement commands, and operable to produce sets of pattern-type coded input signals, each such set representing in abbreviated form a series of blocks of machine tool displacement commands for said machine tool system, and c. a stored program digital computer operably connectable on line with said machine tool system for transmitting machine tool displacement commands thereto, and operably connectable on line with said input device for receiving said displacement-type coded input signals and said sets of pAttern-type coded input signals from said input device, and including a computer memory and a stored program stored in said computer memory for controlling the conversion by said computer of said displacement-type coded input signals into corresponding machine tool displacement commands and for controlling the conversion of said sets of pattern-type coded input signals into respective series of blocks of machine tool displacement commands.
 40. The combination of claim 39 with said input device being operable to generate a displacement-type coded input signal including a series of displacement values whose algebraic sum represents a coordinate value specifying a movement of the worktable relative to one of said axes, and said stored program digital computer under the control of said stored program being operable in response to said coded input signal including said series of displacement values to compute said algebraic sum and to generate a block of machine tool displacement commands including said coordinate value and specifying a movement of the worktable relative to the respective axes.
 41. The combination of claim 40 with said input device including a manually operable line-type character generator for generating in successive line operations thereof successive lines of coded input signals, and being operable to generate said displacement-type coded input signal including said series of displacement values in a single one of said line operations thereof, and a display device including a display region operably connectable with said character generator for displaying successive lines of coded input signals as generated by manual operation of said character generator along respective vertically offset horizontal lines on said display region.
 42. The combination of claim 41 with said manually operable line-type character generator being operable to generate a set of said pattern-type coded input signals representing a series of blocks of machine tool displacement commands in a single one of said line operations of said character generator. 